Audio Codec Concealment Parameters for Lost Frame Reconstruction

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Solution Overview

Problem

Existing error concealment mechanisms in audio codecs are inadequate for effectively reconstructing defective audio frames in VoIP systems, particularly in environments with high packet loss ratios, jitter, and reordering.

Innovation Solution

The proposed solution involves embedding error concealment helper parameters in the bitstream, which are used by the decoder to enhance concealment when an original frame is lost, corrupted, or delayed. These parameters are selectively transmitted to minimize bitrate while maintaining good error concealment quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If redundant copies of audio frames are transmitted to enable error concealment, then reliability of audio transmission is improved, but bitrate increases

Engineering Contradiction:

Improveerror concealment qualityVSAvoidbitrate

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent extracts only the essential parameters needed for error concealment (spectral envelope parameters, excitation parameters, gain values) from the complete audio frame and transmits them as separate redundant data. This selective extraction maintains error concealment quality while significantly reducing the bitrate compared to transmitting full redundant frame copies.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The audio frame is segmented into its constituent parameters (spectral envelope, excitation signal, gain values), and only the critical segments necessary for reconstruction are transmitted as redundant data. This segmentation allows the system to send minimal necessary information rather than complete frame copies.

Inventive Principle:

Principle #1Segmentation

2Reliability

If parameters for enhancing concealment are transmitted in the bitstream, then error concealment quality is improved, but device complexity increases

Engineering Contradiction:

Improveframe reconstruction qualityVSAvoidencoder and decoder complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the representation parameters by transmitting specific audio parameters (spectral envelope parameters, excitation parameters, gain values) instead of complete frame data. The decoder uses these parameter changes to reconstruct the audio frame, balancing reconstruction quality with manageable device complexity.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Instead of copying complete audio frames, the patent creates parameter-based copies that can be transmitted efficiently. The decoder copies and applies these parameters to reconstruct the original frame, reducing the complexity of both encoder and decoder while maintaining concealment quality.

Inventive Principle:

Principle #26Copying

Data Source

PatentUS12266375B2Encoder, decoder and method for encoding and decoding audio content using parameters for enhancing a concealment

Publication Date: 2025.04.01 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV

AI summary

Described are an encoder for coding speech-like content and/or general audio content, wherein the encoder is configured to embed, at least in some frames, parameters in a bitstream, which parameters enhance a concealment in case an original frame is lost, corrupted or delayed, and a decoder for decoding speech-like content and/or general audio content, wherein the decoder is configured to use parameters which are sent later in time to enhance a concealment in case an original frame is lost, corrupted or delayed, as well as a method for encoding and a method for decoding.